It points to a psychological aspect. It's commonly known that psychological issues aggrevate stuttering. But it's not the rootcause. And stuttering is a communication disorder, not just a speech one. Thats why most dont stutter when alone. Thats a low stress situation that doesnt trigger your stuttering threshold. https://www.nih.gov/news-events/news-releases/researchers-discover-first-genes-stuttering https://www.sciencedaily.com/releases/2017/01/170103162356.htm How do you explain these findings of a neurological rootcause for stuttering?